1. Field of the Invention
The invention relates generally to a photographic film processing apparatus. More particularly, the invention relates to an apparatus for treating exposed film in one or more processing liquids in a manner which assures the positive application of each processing liquid to the emulsion side of the film as the film is transported through the processing liquid.
2. Description of the Prior Art
The processing of photographic film involves a series of steps such as developing, bleaching, fixing, rinsing, and drying. These steps lend themselves to mechanization by conveying long strips of film sequentially through a series of stations or tanks, each one containing a different processing liquid appropriate to the process step at that station.
Typically, the filmstrip being processed is immersed in and drawn through a developing liquid or other processing liquid. The thoroughness and therefore the quality of processing depends on, among other things, a thorough interaction of the film emulsion and the processing liquid. For effective and quality processing, some movement of the processing liquid, i.e. "agitation", is required to assure that fresh liquid is continually brought into contact with the film emulsion.
The Cross-Referenced Applications
In the first patent application (Ser. No. 064,420) cross-referenced above, there is disclosed a photographic film processor which includes an upright processing rack immersed in a processing liquid tank. The upright rack has two oppositely spaced pairs of mating vertical rack panels, each pair defining a vertical guide slot for an endless timing belt and at least one vertical film processing channel. The endless timing belt extends over a drive sprocket at the top of the processing rack, over an idler sprocket at the bottom of the rack, and along the two vertical guide slots defined by the respective opposite pairs of vertical rack panes. The timing belt has inner teeth for engagement with the sprockets and outer teeth for engagement with a flexible film leader card to which at least one exposed filmstrip is secured. Rotation of the drive sprocket advances the timing belt continuously down one vertical guide slot and up the other in order to pull the exposed filmstrip down a vertical film processing channel in one pair of rack panels and up a vertical processing channel in the opposite pair of rack panels. A processing liquid is pumped into a central vertical cavity between the two opposite pairs of vertical rack panels and is constrained for positive flow through numerous rectangular inlet openings in each inner rack panel at either side of the central cavity. The processing liquid is directed against the emulsion side of successive sections of the filmstrip being pulled along the vertical processing channels, and out of corresponding outlet openings in each outer rack panel proximate the walls of the processing tank. Then, the used liquid flows downwardly between each outer rack panel and the tank walls to drain through an outlet port at the tank bottom.
In the second patent application (Ser. No. 064,421, now U.S. Pat. No. 4,736,222) cross-referenced above, a liquid distribution box is disposed in the central vertical cavity between the two opposite pairs of vertical rack panels to receive the processing liquid which would otherwise be pumped into that cavity. The distribution box includes respective series of staggered relatively small orifices positioned to discharge the processing liquid in a jet-like manner from the interior of the box, through the rectangular inlet openings in each inner rack panel, and against the emulsion side of successive sections of the filmstrip being pulled along the vertical processing channels. The small orifices effect an improved agitation of the processing liquid adjacent the emulsion side of the film sections in the processing channels.